This invention relates to a four-way selector valve and more particularly to a four-way selector valve which has a main valve equipped with a relief valve for discharge pressure as an auxiliary valve.
Conventionally, an air conditioner used for air-conditioning a room or for a similar purpose allows for cooling or heating depending on seasons by switching the flowing direction of refrigerant with a selector valve.
FIG. 8 illustrates an example of a cooling/heating cycle of an air conditioner using the selector valve. For this cycle, a compressor C, a selector valve SV, heat exchangers E1 and E2, and an electronic linear control valve T are connected. As indicated with solid-line arrows, the refrigerant as used for the cooling operation flows through the compressor C, the selector valve SV, an outdoor heat exchanger E1, the electronic linear control valve T, and an indoor heat exchanger E2 in this order. The refrigerant then completes the circulation by returning through the selector valve SV to the compressor C. In contrast, as indicated with dot-dash lines, the refrigerant as used for the heating flows through the compressor C, the selector valve SV, the indoor heat exchanger E2, the electronic linear control valve T, and the outdoor heat exchanger E1 in this order. The refrigerant then completes the circulation by returning through the selector valve SV to the compressor C.
As an example of the selector valve, an art for a four-way selector valve was proposed. (See, e.g., Japanese Utility Model Registration No. 2523031). The proposed art comprises an electromagnet provided on a valve main body, a valve seat mounted at the bottom of the main body, and a rotatable valve provided in the valve main body. The valve seat has, at given angles and spacing, a discharge pressure passage which introduces the discharge pressure of the compressor, a suction pressure passage which introduces the suction pressure, a passage hole for an indoor heat exchanger and a passage hole for an outdoor heat exchanger, which lead to the respective heat exchangers. The rotatable valve is formed from plastic magnet, and has a guide hole which may alternately connect the discharge pressure passage to one of the two passage holes, and a connecting groove which may alternately connect the suction pressure passage to one of the two passage holes. The discharge pressure passage is provided with a conduit whose leading end extrudes to the end of the guide hole. The extruding part of the conduit makes contact with the end of the guide hole, thereby serving as a stopper to limit the rotation of the valve.
As another example of a similar four-way selector valve, an art is proposed for a four-way selector valve comprising (a) a valve seat which has a discharge pressure passage, a suction pressure passage, a passage hole for an indoor heat exchanger and a passage hole for an outdoor heat exchanger, (b) a freely sliding main valve which switches to one of the passage holes, (c) a valve chest which is formed in the main body of the valve by covering all of the passage holes with the main valve, (d) an auxiliary valve which opens/closes the suction pressure passage using magnetic force, and (e) a spring which connects the auxiliary valve and the main valve; wherein the diameter of the discharge pressure passage is smaller than that of the suction pressure passage (see, e.g., Japanese Examined Patent Publication No. 1-32389/1989).
Among the conventional arts, the rotatable valve or a four-way selector valve disclosed in the Japanese Utility Model Registration No. 2523031 uses switching between the flow paths for refrigerant via the discharge pressure passage, the passage hole, the suction pressure passage, and the other passage hole, which is performed inside and outside the main valve. The suction pressure occurs inside the main valve, while the discharge pressure occurs at high pressure outside the main valve. Therefore, there is a pressure difference across the main valve, which tends to cause the switching operation to become heavy. For this four-way selector valve, no particular consideration is given to make easier and quicker the switching operation between the flow paths for refrigerant.
Among the conventional arts, the four-way selector valve according to Japanese Examined Patent Publication No. 1-32389/1989 uses switching between flow paths for refrigerant by the main valve after eliminating the pressure difference across the main body of the valve. Since the main valve is rotated by the elongation and compression of elastic members, no special consideration is given to make quicker the switching operation between the flow paths for refrigerant, nor to the reliability of the four-way selector valve.
The object of the invention is to provide a four-way selector valve which provides easier and quicker switching between flow paths for refrigerant, assures higher reliability, and allows itself to be configured more simply to decrease product cost. In order to accomplish the object, the four-way selector valve of the present invention basically comprises a motor which has a stator and a rotor, a case, and a main body. The main body includes a main valve and a valve seat, both of which are arranged in a valve chest within the case. The valve seat has a suction pressure passage led to a suction port of a compressor, and a discharge pressure passage led to a discharge port of the compressor. The valve seat further has two passage holes led to indoor and outdoor heat exchangers, respectively. The main valve has a connecting part which selectively connects the suction pressure passage to one of the two passage holes, and a pressure equalization orifice which links the connecting part and the valve chest. The rotor comprises a rotor sleeve having the auxiliary valve which opens or closes the pressure equalization orifice in order to transfer pressure. The operating pin moves the position of the main valve. The rotor of the motor rotates the auxiliary valve on the main valve and slides the main valve on the valve seat via the operating pin.
The four-way selector valve of the invention, which is configured as described above, may have, on the main valve, an auxiliary valve which moves pressure inside and outside the main valve. The rotation of the rotor may turn the auxiliary valve to rotate on the main valve, thereby to open or close the pressure equalization orifice so that pressure may move between the connecting part and the valve chest. In addition, the main valve slides on the valve seat in the valve chest. Therefore, the number of operating parts may be reduced, the configuration of the selector valve may be made simpler, the reliability of the inverter valve can be improved, and the switching operation between flow paths for refrigerant can be performed easily and quickly by the main valve.
Another embodiment of the four-way selector valve according to this invention is that the auxiliary valve may be a relief valve, located between the rotor and the main valve, retained to the rotor sleeve, and mounted on the main valve so that it may slide thereon. Alternatively, the rotor sleeve may be equipped with a supporting shaft concentric to the rotational center of the main valve, and the operating pin may be retained to the rotor sleeve and turns the main valve while rotating together with the rotor.
Yet another embodiment of the four-way selector valve according to the invention is that the supporting shafts at the top and bottom of the rotor sleeve may be provided with elastic members which energize or press the auxiliary valve and the main valve toward the valve seat. Alternatively, the valve seat may be provided with a main valve stopper which limits the rotation range of the main valve and that the main valve has a stopper contactor which makes contacts with the main valve stopper. The position of switching by the main valve between the flow paths for refrigerant can securely be regulated, and the production cost for the main valve can be reduced if a same material is used for the stopper contactor and the main valve.
Still another embodiment of the four-way selector valve according to the invention is that either the main valve stopper or the stopper contactor comprises a magnet and that the other consists of a magnetic substance. The switching position for the flow paths for refrigerant can be more securely retained by the magnetic force of the main valve stopper or the stopper contactor, and the vibration resistance of the four-way selector valve can be further improved.
Another embodiments of the four-way selector valve according to the invention is that at least one of the main valve, the auxiliary valve, and the valve seat may be coated with lubricative anodized aluminum film, which improves the lubricative property in sliding the main valve or the auxiliary valve. As a result, the sliding friction may become so low that the stable operation can be performed.